The invention relates to a method and to a corresponding apparatus for identifying an erroneous quiescent current behavior by a vehicle.
Vehicles (particularly road and/or motor vehicles, such as e.g. automobiles, trucks or motorcycles) typically have a battery for storing electric power. Electric power from the battery is used to operate selected electrical loads (e.g. a warning system for theft prevention or a keyless entry function of the vehicle) even in the idle state of the vehicle. Therefore, even in the idle state of the vehicle, the battery provides what is known as a quiescent current.
An increased quiescent current can result in the charge level of the battery falling after the vehicle has been standing for a period of time to the extent that the vehicle may no longer be able to be started. For this reason, it is advantageous to detect in a reliable manner a situation in which there is an erroneously increased quiescent current in order to be able to initiate countermeasures at an early stage.
Therefore, the present document is concerned with the technical object of detecting the presence of a quiescent current error in a reliable manner.
This and other objects are achieved in accordance with the embodiments of the invention.
According to one aspect, a method for determining a quiescent current threshold value for a vehicle electrical system of a vehicle (e.g. for a road vehicle, such as an automobile, a truck or a motorcycle) is described. The quiescent current threshold value can be used to identify a quiescent current error. The vehicle electrical system of a vehicle typically includes an energy store for electric power (e.g. a rechargeable battery). The energy store can provide electric power for one or more electrical loads of the vehicle electrical system. In this case, the quiescent current of the vehicle typically includes the current (or corresponds to the current) that is needed for the operation of one or more electrical loads of the vehicle in an idle state of the vehicle (particularly when an engine of the vehicle is switched off and/or when a vehicle is locked). Exemplary electrical loads that give rise to a quiescent current are a theft warning system and/or a keyless entry function (also known by the name “convenient entry”) of the vehicle.
The method comprises the determination of a multiplicity of quiescent current data records of a corresponding multiplicity of vehicles. The vehicles are typically different vehicles. The different vehicles can have different properties and/or operating states. The properties and/or operating states of a vehicle can be described on the basis of one or more vehicle parameters.
The quiescent current data record of a vehicle can particularly include a quiescent current measured value of the vehicle and at least one value for one or more vehicle parameters of the vehicle. The quiescent current measured value can be captured by a sensor (e.g. by a battery sensor) of the vehicle.
The one or more vehicle parameters of a vehicle can describe one or more properties and/or states of the vehicle. The values for the one or more vehicle parameters may be stored in a memory unit of the vehicle, and can thus be provided together with the quiescent current measured value of the vehicle as a quiescent current data record. By way of example, the one or more vehicle parameters can include information about one or more of: a manufacturer of the vehicle, a type of the vehicle, a series of the vehicle, features of the vehicle (e.g. the presence of a keyless entry function), an ambient temperature of the vehicle (e.g. an average ambient temperature), a humidity in surroundings of the vehicle (e.g. an average humidity) and/or a region (e.g. a cold region or a hot region) in which the vehicle is operated.
Hence, a multiplicity of quiescent current data records can be determined during the operation of a multiplicity of vehicles. Given a relatively large number of quiescent current data records and/or a relatively broad differentiation of vehicles, it is thus possible to provide a statistically relevant overview of the quiescent currents of vehicles.
The method further comprises the determination of a multiplicity of classes by cluster analysis of the multiplicity of quiescent current data records. In other words, on the basis of the multiplicity of quiescent current data records, it is possible for a classifier to be determined. This can be accomplished by using a cluster algorithm and/or a classification method and/or a machine learning method. A class from the multiplicity of classes comprises a vehicle group, which is described by one or more values for one or more vehicle parameters, and a class quiescent current for the vehicle group. Typically, the cluster analysis combines measured values into different classes. From the values of the one or more vehicle parameters of the quiescent current data records, it is possible to determine the vehicle group of a class. Furthermore, from the quiescent current measured values of the quiescent current data records, it is possible to determine the class quiescent current of the class (e.g. as a mean value of the quiescent current measured values).
For determination of the classifier, the cluster analysis can take into consideration one or more conditions. In particular, a predefined number of classes can be stipulated. Alternatively or additionally, a predefined difference between the class quiescent currents of different classes (i.e. a predefined distance between the classes) can be stipulated. This allows the classifier to be matched to the respective circumstances of a set of vehicles that is to be examined.
The method further comprises the determination of a quiescent current threshold value on the basis of at least one of the class quiescent currents of the multiplicity of classes. In this case, the determination can include particularly multiplication of a class quiescent current by a predefined factor. The predefined factor allows the sensitivity of a method for detecting a quiescent current error to be adjusted.
The method described allows quiescent current threshold values for different vehicles to be determined in a precise and differentiated manner. On the basis of the quiescent current threshold values determined in this manner, it is possible for the presence of a quiescent current error in the vehicle electrical system of a vehicle to be detected in a reliable manner.
According to a further aspect, a method for identifying a quiescent current error in a vehicle electrical system of a first vehicle is described. The method includes the determination of one or more first values of one or more vehicle parameters of the first vehicle. On the basis of the first values of the one or more vehicle parameters, it is possible to describe properties and/or states of the first vehicle.
Furthermore, a classifier having a multiplicity of classes can be provided. The classifier may have been determined on the basis of the methods described in this document. In this case, a class of the classifier may include a vehicle group that is described by one or more values of one or more vehicle parameters. Moreover, a class may include a class quiescent current for the relevant vehicle group. The classifier may be configured to assign a respective class quiescent current to a vehicle group. In other words, the classifier can provide a vehicle that is covered by a particular vehicle group with the quiescent current that is to be expected for this vehicle (as the class quiescent current of the particular vehicle group).
The method further comprises the determination of a first vehicle group of the first vehicle on the basis of the classifier and on the basis of the one or more first values of the one or more vehicle parameters of the first vehicle. In particular, the first vehicle can be assigned to a first vehicle group on the basis of the one or more first values of the one or more vehicle parameters. This can involve that vehicle group of the classifier whose values for the one or more vehicle parameters come closest to the first values (e.g. on average) being selected.
Moreover, the method comprises the determination of a first quiescent current threshold value for the first vehicle on the basis of the class quiescent current of the first vehicle group. In particular, this can be accomplished by multiplying the class quiescent current of the first vehicle group by a predefined factor.
Furthermore, the method comprises the identification of a quiescent current error in the first vehicle on the basis of the first quiescent current threshold value. This can be accomplished by determining a present quiescent current of the first vehicle. The present quiescent current can then be compared with the first quiescent current threshold value. A present quiescent current that reaches or exceeds the first quiescent current threshold value may be an indication of the presence of a quiescent current error.
As already explained above, the determination of the quiescent current threshold value on the basis of a classifier can ensure that quiescent current errors can be detected in a reliable manner.
The method may further comprise the initiation of a measure for correcting the quiescent current error when a quiescent current error has been identified. Exemplary measures are setting an error memory entry, outputting an error report and/or notifying the vehicle keeper and/or the garage via a telecommunication service.
According to a further aspect, a control unit for a vehicle is described. The control unit may be configured to perform a method as described herein. Alternatively or additionally, the control unit may be configured to determine an indicator of a quiescent current of a vehicle electrical system of the vehicle (e.g. using a sensor of the vehicle). The control unit may further be configured to transmit the determined indicator of the quiescent current via a communication unit (particularly via a wireless communication unit) of the vehicle to a unit outside the vehicle. In particular, the indicator of the quiescent current can be provided as a quiescent current data record for determination of a classifier. The control unit can therefore help to provide quiescent current data records from the operation of the vehicle for a central unit for determination of the classifier.
The control unit may further be configured to receive a quiescent current threshold value (e.g. via a wireless communication unit of the vehicle). On the basis of the quiescent current threshold value, it is then possible for the presence of a quiescent current error to be identified. As such, it may be possible for an updated classifier to be taken as a basis for updating and providing quiescent current threshold values. This allows improved identification of quiescent current errors.
According to a further aspect, a vehicle (e.g. an automobile, a truck or a motorcycle) is described that includes a control unit as described herein.
According to a further aspect, a software (SW) program is described. The SW program can be configured to be executed on a processor (e.g. on a controller of a vehicle) and, as result, to perform a method as described herein.
According a further aspect, a storage medium is described. The storage medium may comprise an SW program that is configured to be executed on a processor and, as result, to perform a method as described herein.
It should be noted that the methods, apparatuses and systems described in this document can be used either on their own or in combination with other methods, apparatuses and systems described in this document. Furthermore, all aspects of the methods, apparatuses and systems described in this document can be combined with one another in many and diverse ways.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.